What is Peppol? The e-invoicing network and BIS Billing 3.0 explained

Peppol is how a growing number of European businesses send invoices to each other without e-mail or paper. You send an invoice once, from your own software, and it lands directly in your customer's software, whichever provider they use. In Belgium this has been the legal default for B2B invoices since 1 January 2026.

This page explains how the network works, what a Peppol invoice contains, where Peppol is required and how to get connected. If you are in Belgium, our Peppol Belgium guide covers the legal rules in full.

Peppol in one paragraph

Peppol is two things at once: a network for exchanging business documents and a set of document specifications for what travels over it. It is governed by OpenPeppol, which describes itself as "a non-profit international association established under Belgian law". OpenPeppol stresses that Peppol is "not a portal, or a provider of exchange services". It is the rulebook. The actual sending is done by certified service providers, often called access points.

How the four-corner model works

OpenPeppol calls its architecture the four-corner model. The four corners are:

1. The supplier (corner 1) creates the invoice in its invoicing software.
2. The supplier's service provider (corner 2) takes the invoice and finds out where the customer is registered on the network.
3. The customer's service provider (corner 3) receives the invoice.
4. The customer (corner 4) sees the invoice in its own software.

OpenPeppol says the model lets buyers and suppliers "connect via any Peppol-accredited Service Provider". That is the main difference from closed portals: you do not need an account with your customer's system, and your customer does not need one with yours.

Peppol IDs: your address on the network

Every participant has a Peppol ID, made up of a scheme code and an identifier. Belgian businesses are registered at least under their enterprise number with scheme 0208. A supplier can therefore send to 0208:<company number> without asking for anything else.

Before you send, you can check whether a customer is registered in the public Peppol Directory. Our Peppol Directory guide explains how to search it and what the results mean.

Peppol BIS Billing 3.0: what a Peppol invoice contains

The invoice format is Peppol BIS Billing 3.0. OpenPeppol's documentation describes it as "a Core Invoice Usage Specification (CIUS) of EN 16931", and states that "any instance documents compliant to this specification will be compliant with the European Standard".

In practice that means:

• The invoice is an XML file in UBL syntax. There are two document types: UBL Invoice (type code 380 and related codes) and UBL Credit Note (type code 381 and related codes).
• The data model is EN 16931, the European standard also behind XRechnung, ZUGFeRD and Factur-X.
• Peppol adds its own rules on top, so a file can be EN 16931-valid and still fail Peppol validation.

A Peppol BIS invoice identifies itself in two header fields:

Attachments such as a PDF copy, timesheets or a spreadsheet travel inside the XML. In Belgium the FPS Finance lists pdf, png, jpg, csv, xlsx and ods, and says attachments must not be sent separately by e-mail. The structured invoice is the legal invoice. A PDF copy is only for convenience.

Where Peppol is required

Belgium

Since 1 January 2026, structured e-invoices have been mandatory between VAT taxable persons established in Belgium, with Peppol BIS Billing 3.0 as the default. Issuing and receiving started on the same day, with no phasing by size. The general penalty tolerance ended on 31 March 2026, and the self-billing tolerance on 30 June 2026.

Businesses that are not established in Belgium are outside the obligation, even with a Belgian VAT number, under the law of 10 February 2026. For public buyers, Belgium uses Mercurius via Peppol for contracts published after 1 March 2024, generally from €3,000 excluding VAT and lower for federal authorities.

Germany

Germany's B2B rule asks for an EN 16931-compliant e-invoice and leaves the format and channel to the parties. The BMF names Peppol BIS Billing 3.0 UBL as an accepted format. You can send it over Peppol, by e-mail or any other agreed channel. Businesses established in Germany must receive e-invoices since 1 January 2025, and issue them from 1 January 2027 or 2028 depending on turnover. See our Germany guide.

France

France built its own network of approved platforms (plateformes agréées). Invoices go from the issuer's platform to the recipient's platform, which also report data to the tax administration. The legal formats are UBL, CII and Factur-X. Some French platforms say they are also connected to Peppol, but that is a vendor feature, not the French legal channel. See our France guide.

Cross-border, from 2030

Under the EU's VAT in the Digital Age package (ViDA), intra-EU B2B transactions become subject to mandatory e-invoicing based on EN 16931, and near-real-time digital reporting, from 1 July 2030. Belgium will implement intra-EU reporting by that date at the latest.

How to get connected to Peppol

You cannot register on Peppol directly. The usual routes are:

1. Invoicing or accounting software with Peppol built in. The vendor is or uses a certified service provider and registers you, usually under your company number.
2. A dedicated access point service. Some providers offer sending by e-mail forwarding or API, aimed at developers or high volumes.

The Belgian FPS Finance lists more than 250 compliant software solutions. There is no free government tool, and the former Hermes fallback service was reportedly shut down at the end of 2025. Our Peppol access point comparison covers the main options for Belgium and which offer free plans.

What changes when you receive invoices over Peppol

Once you are registered, Belgian suppliers send your invoices to your Peppol inbox, not your e-mail. A few practical points follow from the Belgian rules:

• The structured file is the invoice. A PDF copy may travel with it, but only the XML counts legally.
• If you cannot receive, your supplier has a fallback. Since the law of 10 February 2026, a supplier whose customer technically cannot receive may issue paper, or PDF with the customer's consent. The customer remains liable for not being able to receive.
• Input VAT. In principle a structured e-invoice is needed to deduct VAT. The FPS Finance applies "substance over form", and if the supplier was not ready, the customer keeps the deduction on the alternative invoice.

For a business that only sells to consumers, outgoing invoices are out of scope, but it must still be able to receive from Belgian suppliers.

How to check a Peppol invoice

If you receive a Peppol file outside your software, or want to test what your tool produces, our validator opens it in your browser, shows it as a readable invoice and runs the official CEN EN 16931 rules plus the OpenPEPPOL BIS Billing 3.0 rules. The file is not uploaded anywhere.

The validator checks the business rules, not XML schema (XSD) conformance, and it cannot tell you whether the VAT treatment is right. For questions of substance, ask your accountant or tax adviser.

Peppol terms you will meet

• Access point / service provider: the certified company that sends and receives on your behalf.
• Peppol ID / participant identifier: your address on the network, such as 0208 plus a Belgian company number.
• Peppol Directory: the public search of registered participants.
• BIS (Business Interoperability Specification): a Peppol document standard. BIS Billing 3.0 covers invoices and credit notes.
• CIUS: a set of extra rules on top of EN 16931. Peppol BIS and XRechnung are both CIUS.

More definitions are in our glossary.